The present invention relates to the manner in which a vehicle navigation system communicates a calculated route to a driver. More specifically, the present invention relates to the selection of audio files used to construct maneuver instructions which alert the driver to upcoming maneuvers.
Vehicle navigation systems employ a variety of methods for communicating a route to a driver. One conventional method employs voice prompts or maneuver instructions to inform the driver of an upcoming maneuver. By using maneuver instructions, the system allows the driver to keep his eyes on the road.
Currently available vehicle navigation systems construct maneuver instructions from previously stored voice fragments. By way of example, the fragments may include numbers and directions, e.g. one, north, south, etc. Current vehicle navigation systems typically store a single audio file for a voice fragment. Thus, once a maneuver is determined, the same voice fragment is used by the system to present a voice fragment within a maneuver instruction regardless of the upcoming maneuver.
Unfortunately, as voice intonation often changes in natural speech based on content, this static method often does not present a natural sounding instruction.
It is, therefore, desirable that techniques be developed by which more natural sounding maneuver instructions are generated.
The present invention is directed to systems and methods for generating maneuver instructions and presenting them to the user of a vehicle navigation system. The maneuver instructions are generated from voice fragments whose audio files may be flexibly selected to improve presentation of routing information provided by the vehicle navigation system.
According to one embodiment, the system may maintain multiple audio files for a fragment used to construct maneuver instructions wherein the multiple audio files for the same fragment each present a different voice intonation. After receiving a maneuver instruction, the system selects a particular audio file for each fragment in the maneuver instruction. In some embodiments, an audio file is selected for a fragment based on the presence of other fragments included in a maneuver instruction. By providing this flexible selection of audio files for voice fragments, voice guidance of the present invention more closely resembles natural human speech.
According to a specific embodiment, once a route has been calculated and maneuvers have been determined, the system selects audio files for each fragment of a maneuver instruction in a manner determined in part by one or more fragments of the maneuver instruction. According to some embodiments, the present invention determines whether the last fragment in a maneuver instruction is a descriptor. The system then selects an audio file for a fragment preceding the descriptor based on the presence of the descriptor. In a specific embodiment wherein a descriptor is included, audio files are selected such that the voice intonation of the descriptor decreases in frequency, i.e., ends with a xe2x80x9cdownxe2x80x9d emphasis, while the fragment preceding the descriptor increases in frequency, i.e., ends with an xe2x80x9cupxe2x80x9d emphasis.
According to a specific embodiment, the present invention improves voice guidance by determining whether a number included in a maneuver instruction is presented alone or is concatenated with another number. The system then selects an appropriate audio file or files for numeric fragments in the maneuver instruction based on this determination. The audio files to be selected from may vary in voice intonation.
Thus, according to the invention, a method and apparatus are provided for providing route guidance to a user of a vehicle navigation system. A route is generated which corresponds to a plurality of maneuvers. The maneuver instruction corresponding to each maneuver is generated. Generating the maneuver instruction includes selecting an audio file for each fragment of the maneuver instruction. Selection of an audio file for a voice fragment may include flexible selection between multiple audio files for the same fragment. In turn, the maneuver instructions are audibly presented to a user of the vehicle navigation system. The flexible selection improves presentation and may improve recognition of the maneuver instructions.
In one aspect, the method includes selecting an audio file corresponding to a first voice fragment included in the maneuver instruction based on a second voice fragment included in the maneuver instruction.
In another aspect, the invention relates to a method for generating a maneuver instruction in a vehicle navigation system. The method includes receiving a maneuver instruction which comprises a first sentence portion, a second sentence portion and a maneuver information portion. The portions each comprise one or more voice fragments. The method also includes selecting a first audio file corresponding to the first sentence portion. The method further includes determining if the last voice fragment includes a number. The method additionally includes selecting a second audio file for the second to last voice fragment based on whether the last voice fragment includes a number. The method also includes presenting the first and second audio files.
Thus, the present invention provides a vehicle navigation system which flexibly communicates maneuver instructions for upcoming maneuvers in a manner which flexibly selects audio files for voice fragments of the maneuver instructions. Advantageously, the present invention provides advanced presentation and communication of maneuver instructions to the user of a vehicle navigation system. By flexibly constructing the presentation of maneuver instructions to more closely resemble natural human speech, the driver may more easily recognize the content of maneuver instructions issued by the navigation system.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.